Matlab Simulink of COST231-WI Model IJWMT-V2-N3-1

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I.J. Wireless and Microwave Technologies,2012, 3, 1-8Published Online June 2012 in MECS (http ://www.mecs-press .net)

DOI: 10.5815//ijwmt.2012.03.01

Available online athttp://www.mecs-press.net/i jwmt

Matlab Simulink of COST231-WI Model

Yihuai Yanga, Dongya Shenb, Yonggang Xiec, Xiangde Lid

a,c,dAcademy of telecommunications technology, Kunming University, Kunming, China

a,bSchool of Information Science & Eng., Yunnan University, Kunming, 650091, China

Abstract

Simulink is the integrated environment of system modelling and simulation, which is being widespread used.

This paper describes the MATLAB visual simulation of the propagation path loss model for te lecommunication

systems. We simulated the whole process of COST231-Walfisch-Ikegami model with high accuracy, built a

visual simulation frame and the path loss curves are given. This method can be used in studying other

propagation path loss models in propagation environments .

Index Terms: Path loss; wireless communication; model; COST231-Walfisch-Ikegami ; Simulink

2012 Published by MECS Publisher. Selection and/or peer review under responsibility of the Research

Association of Modern Education and Computer Science

1. IntroductionThe tremendous growth of wireless communication systems and especially mobile radio systems requires

radio coverage prediction models that provide accurate results and fast processing time for several types of

environments , which includes a large nu mber of parameters describing the propagation environment. Due to the

complexity and instability of radio transmiss ion in wireless communications channels, it is very important to get

the knowledge about the characteristics of wireless communication and use the suitable propagation models.

Path loss is a major component in the analysis and design of the link budget of a telecommunication system.

Path loss models are useful planning tools allow the radio network designer to reach optimal levels for the base

station deployment and configuration while meeting the expected service level requirements. There are somewell-known conventional prediction models such as the Okumura-Hata model[1], COST231-Hata model[2], ITU

Terrain Model[3], Egli model[3], Sakagami model[4], and COST231-Walfisch-Ikegami model[5]. But there

have some deficiencies in these models. For example, the response of Okumura-Hata model is much slowly to

the fast change signal of the suburb area, the error is 10 ~14dB, and being a set of curve, it is inconvenience to

use. ITU Terrain Model is considered valid for losses over 15 dB and is not applicable to terrains where

irregularities are high. Egli Model predicts the path loss as a whole and does not subdivide the loss into free

space loss and other losses. COST-Hata model requires the base station antenna higher than all adjacent rooftops.

The paper is supported by Kunming University Natural Science Foundation; National Science and Technology MajorProject(No:2010ZX03007-001); Key Project Of International Coorperation of Yunnan (2009AC010); State Key Labof Millimeter Waves

Foundation (No.K200814).

* Corresponding author.E-mail address:

[email protected];

[email protected]
http://www.mecs-press.net/ijemehttp://www.mecs-press.net/ijemehttp://www.mecs-press.net/ijemehttp://en.wikipedia.org/wiki/Link_budgetmailto:[email protected];mailto:[email protected];mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected];http://en.wikipedia.org/wiki/Link_budgethttp://www.mecs-press.net/ijeme


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2 Matlab Simulink of COST231-WI Model

ITU Terrain Model's output is only as good as the data on which it is based and the LOS model it is used to

correct.

Compared to other models, the accuracy of the COST231Walfish-Ikegami Model is quite high. It is because

in urban environments especially the propagation over the rooftops (multiple diffractions) is the most dominant

part. Only wave guiding effects due to mult iple reflections are not considered[5]. So, we selected COST231

Walfish-Ikegami Model for numerical analysis and Matlab Simulink simulation.

2. Cost231-Walfisch-Ikegami modelThe COST231-Walfisch-Ikegami model (COST231-WI)[5][6][7] is a statistical model on combination of the

Walfisch-Bertoni model[8] and Ikegami model[9]. It is proposed by COST 231and has been accepted by the

ITU-R. It is with no considerations of topographical database of buildings , and is res tricted to flat urban terrain.

COST231-WI model is one of the most popular models in radio propagation prediction in urban UMTS

network planning and is included into Report 567-4. The estimation of path loss agrees rather well with

measurements for base station antenna heights above roof-top level. The model allows for improved path-loss

estimation by consideration of more data to describe the character of the urban environment, namely, the basestation (BS) antenna height hb, the mobile station (MS) antenna height hm, the mean building height hB , the

street width w, the s eparation distance between the rows of buildings b, the the distance between BS and MS d,and the angle of incidence from the BS to the first diffraction edge . COST231-WI model can be used in thefollow scenario, where MHz2000MHz800 f and km5km02.0 d . The detail parameters and formulation of

this model can be seen in[5][6][7].

COST231-WI model[5][6][7] distinguishes between line-of-sight (LOS) and non-line-of-sight (NLOS)

situations.

In the LOS case, the loss is based on measurements performed in the city of Stockholm:

( ) ( ) mdfdLLOS 20for,log20log266.42 ++= (1)

For the NLOS situations, the path loss of COST231-WI Model is composed of the terms free space loss Lfs ,

roof-top-to-street diffraction and scatter lossLrts and the multiple screen diffraction loss Lmsd:

( )

( )

+

+++=

0

0

msdrtsfs

msdrtsmsdrtsfs

NLOSLLL

LLLLLL (2)

The free-space lossLfs is given by:

dfLfs

lg20lg2044.32 ++= (3)

Where, is frequency in MHz,dis distance in km.

The termLrts describes the coupling of the wave propagating along the multiple-screen path into the streetwhere the mobile s tation is located.

oribrtsLhfwL +++= lg20lg10lg109.16 (4)

Where,Bbb hhh = , w , bh is in m, and the street-orientation fadingLori is defined by:
http://www.awe-communications.com/accuracy.htmlhttp://www.awe-communications.com/accuracy.html


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Matlab Simulink of COST231-WI Model 3

( )( )

+

+

=

905555114.00.4

553535075.05.2

350354.010

oriL(5)

The heights of buildings and their spatial separations along the direct radio path are modeled by absorbing

screens for the determination ofLmsd.

bfkdkkLL fdabshmsd lg9lglg +++= (6)

Where

>+=

00

0)1lg(18

b

bb

bshh

hhL

(7)

=

5.0and,0for6.154

5.0and0for8.054

0for54

dhhd

dhh

h

k

bb

bb

b

a

(8)

>

=01518

081

b

B

b

b

dh

h

h

h

k

(9)

+=

centeranmetropolitfor1925

5.1

densitytreemediumwithcentres

suburbanandcitysizedmediumfor1925

.70

4

f

f

kf

(10)

3. Modelling of Cost231-WI modelMatlab Simulink provides an interactive graphical environment and a customizable set of block libraries that

can design, simulate, implement, and test a variety of time-varying propagation models with advanced

capabilities.

3.1. modelling scheme of COST231-WI ModelThere are five steps for modelling COST231-WI model:

Establish mathematical model. Transfer the nonlinear formulations into computer graphics forms.


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Decompose the COST231-WI model into fundamental subsystems, analyse and find the relationshipbetween them.

Using Matlab Simlink to es tablish simulation sub-model layers and determine the value a lgorithm. Setup and modulate parameters. Setup observe windows, analyse data and waves.

In this paper we decompose the COST231-WI model according to it's s tructure characteristic, abstract themodel's fundamental operation units and analyse connections of them. Then we determine interface, input and

output of each unit, simulation these units in Matlab Simulink and doing holistic analysis[10].

Management of the simulation model is hierarchical. We use two layers of management level. The first level

is doing factors modulate, including parameter, types , and properties of the definition. The second level is doing

files management according to requirement, and share resource platform through .m and .mdl program.

The whole visual procedure is interactive. Users can pause or stop the program in it's running time, and could

read, search and doing comprehensive analysis after the running.

Using the Matlab Simulink to simulate COST231-WI model, we can get the path loss cures directly. It allows

users doing real time communication to the propagation model through SGUI, and allow users intervene

simulation process at any running time. Fig.1 shows the procedure of the COST231-WI simulation.

No

Yes

Fig 1. Flow diagram for COST231-WI model

3.2.Matlab Simulink system model

According to path loss formula of COST231-WI model and the modelling scheme mentioned above, the

established model composed by four subsystems including twelve basic algorithm logic units. Fig.2 shows the

general COST231-WI model.

Reset

Available

End

Start

Decompose the COST231-WImodel and generate modules

Establish the simulation sub-model layers

Put into parameters

Invoking visual simulationprocedure


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Fig 2. Modeling the COST231-WI model

Fig 3. Modeling subsystem of Lfs

Fig 4. Modeling subsystem of Lrts


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Fig 5. Modeling subsystem of Lmsd

3.3. Simulation ResultsFig.6 shows the path loss mean curves of COST231-WI model in different base station height, when other

parameters are the same. Fro m Fig.6 we can see that the higher the base s tation the lower the attenuation. It ismainly because that obstacles are less when the base station is higher.

Fig 6. Path loss for different base station height


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Fig.7 shows the path loss mean curves of COST231-WI model in different frequencies, when other

parameters are the s ame. From Fig.7 we can see that the higher the frequence the higher the attenuation.

Fig 7. Path loss for different frequencies

Fig.8 shows the path loss mean curves of COST231-WI model in two d ifferent areas: the metropolitan center

areas and medium sized city and suburban centres which with medium tree density. From Fig.8 we can see that

the metropolitan center areas ' path loss is higher than the medium sized city's . It is mainly becaus e there are more

obstacles in former environment.

Fig 8. Path loss in different environment

4. ConclusionIn this paper, one of the most famous propagation model COST231-WI model has been implemented in

SIMULINK. A detailed description for both total system and subsystem units was given. Different propagationmodel effects (such as the BS antenna heighthb, the MS antenna height hm, the mean building height hB , the


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street width w, etc. ) were introduced in the model. The performance was tested and compared under different

conditions. The implemented model showed a good capability in prediction the path loss.

Compared with other traditional advanced programming languages, such as C++ and Fortran, Simulink

environment provides powerful high-level mathematical modeling environment for d igital communication

systems, it can realize Graphical modeling and visual simulation in dynamic, it provides a comprehensive

solution for propagation path loss predict to mobile communication systems, and can be widely used foralgorithm development and verification.

References

[1] M. Hata, Empirical formula for propagation loss in land mobile radio services, IEEE Transactions onVehicular Technology, vol. 29, no. 3, Sep. 1980.

[2] European Cooperation in the Field of Scientific and Technical Research EURO-COST231, UrbanTransmission LOSS Models for Mobile Radio in the 900 and 1800 MHz Bands, Revision 2, The Hague,

September 1991.

[3] Ananias Pereira Neto, Edilberto O. Rozal, Evaldo G. Pelaes. Bidimensional Statistics Analysis of theBertoni - Walfisch Propagation Model for Mobile Radio Design in Urban Areas International Microwave andOptoelectronics Conference (IMOC 2003), vol.2.

[4] S.Sakagami,K,Kuboi, Mobile Propagation Loss Prediction for Arbitrary Urban Environment,IEICETrans.Commun.,Vol.J74-B-,No.1,pp.17-25,Jan.1991.

[5] COST 231, Digital mobile radio towards future generation systems, Final Report, COST TelecomSecretariat, European Commiss ion, Brussels, Belgium, 1999.

[6] European Cooperation in the Field of Scientific and Technical Research EURO-COST231, UrbanTransmission LOSS Models for Mobile Radio in the 900 and 1800 MHz Bands, Revision 2, The Hague,

September 1991.

[7] Damosso, E., Action COST 231: a commitment to the transition from GSM to UMTS, IEEEInternational Conference on Personal Wireless Commun ications , 18-19 Aug., 1994.

[8] J.Walfisch and H.L. Bertoni, A Theoretical model of UHF propagation in urban environments, IEEETrans. Antennas Propagat., vol.36, 1988, pp.1788-1796[9] F.Ikegami, T.Takeuchi, and S.Yoshida, Theoretical prediction of mean field strength for Urban MobileRadio, IEEE Trans. Antennas Propagat., Vol.39, No.3, 1991

[10]Yanhua Zhang, Zhanyun Duan, Lansun Shen, Okumura-Hata radio propagation models using visualsimulation, Chinses Jouranal of Radio Science, Vol.16, No.1, 2001. Pp.89-117. In Chinese.
http://en.wikipedia.org/wiki/C++http://en.wikipedia.org/wiki/Fortranhttp://en.wikipedia.org/wiki/Fortranhttp://en.wikipedia.org/wiki/C++

Matlab Simulink of COST231-WI Model IJWMT-V2-N3-1

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